1eu3: Difference between revisions
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[[Image:1eu3.jpg|left|200px]] | [[Image:1eu3.jpg|left|200px]] | ||
'''CRYSTAL STRUCTURE OF THE SUPERANTIGEN SMEZ-2 (ZINC BOUND) FROM STREPTOCOCCUS PYOGENES''' | {{Structure | ||
|PDB= 1eu3 |SIZE=350|CAPTION= <scene name='initialview01'>1eu3</scene>, resolution 1.68Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene> and <scene name='pdbligand=K:POTASSIUM ION'>K</scene> | |||
|ACTIVITY= | |||
|GENE= | |||
}} | |||
'''CRYSTAL STRUCTURE OF THE SUPERANTIGEN SMEZ-2 (ZINC BOUND) FROM STREPTOCOCCUS PYOGENES''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1EU3 is a [ | 1EU3 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Streptococcus_pyogenes Streptococcus pyogenes]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EU3 OCA]. | ||
==Reference== | ==Reference== | ||
Conservation and variation in superantigen structure and activity highlighted by the three-dimensional structures of two new superantigens from Streptococcus pyogenes., Arcus VL, Proft T, Sigrell JA, Baker HM, Fraser JD, Baker EN, J Mol Biol. 2000 May 26;299(1):157-68. PMID:[http:// | Conservation and variation in superantigen structure and activity highlighted by the three-dimensional structures of two new superantigens from Streptococcus pyogenes., Arcus VL, Proft T, Sigrell JA, Baker HM, Fraser JD, Baker EN, J Mol Biol. 2000 May 26;299(1):157-68. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/10860729 10860729] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Streptococcus pyogenes]] | [[Category: Streptococcus pyogenes]] | ||
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[[Category: superantigen fold]] | [[Category: superantigen fold]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 11:00:18 2008'' | ||
Revision as of 12:00, 20 March 2008
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CRYSTAL STRUCTURE OF THE SUPERANTIGEN SMEZ-2 (ZINC BOUND) FROM STREPTOCOCCUS PYOGENES
OverviewOverview
Bacterial superantigens (SAgs) are a structurally related group of protein toxins secreted by Staphylococcus aureus and Streptococcus pyogenes. They are implicated in a range of human pathologies associated with bacterial infection whose symptoms result from SAg-mediated stimulation of a large number (2-20%) of T-cells. At the molecular level, bacterial SAgs bind to major histocompatability class II (MHC-II) molecules and disrupt the normal interaction between MHC-II and T-cell receptors (TCRs). We have determined high-resolution crystal structures of two newly identified streptococcal superantigens, SPE-H and SMEZ-2. Both structures conform to the generic bacterial superantigen folding pattern, comprising an OB-fold N-terminal domain and a beta-grasp C-terminal domain. SPE-H and SMEZ-2 also display very similar zinc-binding sites on the outer concave surfaces of their C-terminal domains. Structural comparisons with other SAgs identify two structural sub-families. Sub-families are related by conserved core residues and demarcated by variable binding surfaces for MHC-II and TCR. SMEZ-2 is most closely related to the streptococcal SAg SPE-C, and together they constitute one structural sub-family. In contrast, SPE-H appears to be a hybrid whose N-terminal domain is most closely related to the SEB sub-family and whose C-terminal domain is most closely related to the SPE-C/SMEZ-2 sub-family. MHC-II binding for both SPE-H and SMEZ-2 is mediated by the zinc ion at their C-terminal face, whereas the generic N-terminal domain MHC-II binding site found on many SAgs appears not to be present. Structural comparisons provide evidence for variations in TCR binding between SPE-H, SMEZ-2 and other members of the SAg family; the extreme potency of SMEZ-2 (active at 10(-15) g ml-1 levels) is likely to be related to its TCR binding properties. The smez gene shows allelic variation that maps onto a considerable proportion of the protein surface. This allelic variation, coupled with the varied binding modes of SAgs to MHC-II and TCR, highlights the pressure on SAgs to avoid host immune defences.
About this StructureAbout this Structure
1EU3 is a Single protein structure of sequence from Streptococcus pyogenes. Full crystallographic information is available from OCA.
ReferenceReference
Conservation and variation in superantigen structure and activity highlighted by the three-dimensional structures of two new superantigens from Streptococcus pyogenes., Arcus VL, Proft T, Sigrell JA, Baker HM, Fraser JD, Baker EN, J Mol Biol. 2000 May 26;299(1):157-68. PMID:10860729
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